Preparation of Ti-Mo-Si alloy powders with enhanced high-temperature oxidation resistance using Ti-10Mo scraps

To recycle Ti alloy scraps and enhance the functionality of the recycled scraps, we manufactured low-oxygen contented Ti-Mo-Si powders using two types of ternary Ti alloy ingots which were prepared by vacuum arc melting of Ti-Mo scrap with different amounts of Si. The weight ratio of Ti-Mo scrap was Ti:Mo=9:1 and Si contents in two alloy ingots were 1 and 2 wt%. The alloy powders were prepared by the hydrogenation-dehydrogenation process and the oxygen atoms were removed by the deoxidation in solid state method. We confirmed that the deoxidation process effectively reduced the oxygen content of Ti-Mo-Si alloy powder from 3,350 ppm to 1,700 ppm. In addition, we confirmed that the high-temperature oxidation resistance was increased by adding Si to Ti-Mo alloys. Thermal gravimetric analysis showed that the weight gain of powders by the oxidation was reduced from 8.85% for Ti-Mo to 7.5% for Ti-Mo-Si at 1,500 °C.